Hydraulic coupling



March 3,' 1959 yF. x. KuGl-:L

` HYDRAULIC couPLING Filed May 19, 1955 2 sheets-sheet 2 United States Patent C) p 2,875,581 HYDRAULIC COUPLING 'Fritz K. Kugel, Heidenheim (Brenz), Germany, assignor `to J. M. Voith, G. m. b. He, Maschinenfabrik, Heidenheim, Brenz, Germany Application May 19, 11955, Serial No. 509,620

In Germany October 1, 1948 Public Law 619, August 23, 1954 Patent expires October `1, 1968 20 Claims. (Cl. 60--54) The present invention relates to hydrodynamic couplings, generally called hydraulic couplings, with rotating containers and is of particular advantage in connection with power transmission systems employing a shortcircuitrotor motor, and 'is also of particular advantage in connection with vehicle drives comprising internal combustion engines.

In power transmission systems `comprising a hydraulic coupling, especially when the drive is elfected by an internal combustion engine or an electric motor operating with a short-circuit rotor, it is desirable Within the normal working range to have minimum slip :and thus to .obtain a maximum efficiency in the hydraulic coupling, and to havea minimum torque transmission whenthe slip is high; Thus, `for example, in a vehicle transmission gear, the torque transmitted by the coupling when vthe `motor is idling should be so small that the stationary vehicle `will not `tend to move. This problemisparticularly acute `with ycouplings having a constant fluid filling, that is AIto say those couplings 4inwhich no externally operated `means :are `provided for regulating the lling.

`-lt is, therefore, an object of this invention tonprovide a hydraulic coupling arrangement in which the torque adapted to be transmitted will with maximum slip up to :the Vpoint where thesdriven shaft is completely braked :000% Eslip) `amount to only I1.5 `to 3 times lthe normal torque transmitted with a slip of `2 to 3%.

A further frequently undesired feature of heretofore known hydraulic couplings with `constant filling consists in that `when directly throwing in `the .drive motor, it is unavoidable that due `to high torques transmitted -by the coupling, shock-like acting 'loadswill occur in the drive system. Thus, for instance, when employing a drive `:a short-.circuit rotor motor the latter when switched on causes `a strong current surge vor -with long feeding `lines causes a great drop in -vo'ltagetand :thereby a drop 'inthe motor torque. A f

Therefore, itis another object of vthis invention to provide rafhydraulic coupling arrangement in which the power `ztransmission ability Aof the hydraulic coupling during the starting .operation is reduced with regard to :that of ordinary coupling designs. Y

` `These and other objects `and advantages of the inven- .ztion will yappear `more clearly from the following specificactionin connection with the accompanying drawings `in which:

eFig. il illustrates a longitudinal section through `a -hy- ,draulic coupling iprovided with coupling bladings and two rotating containers in :conformity with ythe vpresent invention. t i

Eig. 2 `shows two graphs illustrating the respective `torque curves of a hydraulic :coupling according `to the invention and of "an ordinary Jhydraulic coupling.

Pig. L3 shows graphs `illustrating the ymotor torque as depending ton the speed of the tdrive fmotor, and .the .turques respectively obtained during `the starting period by an ordinary hydraulic coupling.`

`luf a hydraulic coupling according so `the yinvention .and

2,875,581 PatentedMar, `I'g, 1959 ice Fig. 4 is a longitudinal` section through a hydraulic coupling similar to that of Fig. l but differing therefrom in that the turbine wheel is provided with walls by means of which the rst rotatable container is screened with regard to the pump wheel or impeller.

Fig. 5 is a hydraulic coupling with a direct connection between the two rotating containers and. with centrifugally controlled discharge valves on the second container.

Fig. 6 is a hydraulic coupling similar to that of Fig. 5 but differing therefrom in that centrifugally `controlled connecting passages are provided between the t-wp containers.

Fig. 7 is a hydraulic coupling in which the inlet and discharge valves lof ythesecond container are coupled to each other.

`General arrangement According to the invention the 4turbine wheel blading of the hydraulic coupling is provided with a smaller-inner diameter than the impeller b lading. -:Furthermore the radially inner portion of the vblade chamber of the turbine wheel communicates with va rotatable container Llocated lradially within the inner Vdiameter of the impeller blading`. The said rotatable container will henceforth be called rst rotatable container or accumulating chamber. The hydraulic coupling according to the invention furthermore comprises a further container rotating with the impeller and henceforth lcalled second rotatable con- 4tainer` This second rotatable container is intended and designed to receive a portion of the coupling liquid. The space of said second rotatable container is located substantially insdo o diameter whiols `about oo rrssposds to ,the medium dia-motor of ytho impollsr bieding. Tho scoood rotatable -oootonor communicates t-hroosh openings at Vits maximum diameter with the blade chamber ,of the impeller. The arrangement .of the second rotatable ,container is' such `thatduring the l standstill of thc hydraulic coupling, .the `working chamber thereof partly discharges .into the second container, whereas said second container `during @the starting period l,due Vto centrifugal force grad- -uolly discharges finto tho working o irooit- In s uoh a :hydraulic coupling, at -sormollrlow slip, for `instance 3%, the flow `in `the vcoupling working chamber is substantially unaffected because the vortex ilow due to thohisll primary and soooodary spoed toi `rotatiorltalros place in the radiallyouter portions ofthe working chamber as is indicated by the arrow ,1,7 in Fig. 1.' At high slip, however, the ,How in the turbine wheel :takes Aplace further radially inwardly and in the `,first rotating container .or accumulator `chamber `due to the low turbine wheel speed. As a result thereof, the vortex ow in (the coupling working chamber Ais disturbed and `,furthermore aportion of the working fluid accumulates -in lthe accumulator chamber and is withdrawn from the working `circuit so that, therefore, at high slip the transmission capacity of the 4coupling is essentially reduced over that of ordinary couplingsf 4When the `hydraulic coupling 4is at a standstill, a portion of the coupling fluid will always `collect in the second container. A This portion of the liquidrernains `during a sudden start v temporarily in said second container and only `gradually is` thrown out therefrom Tby centrifugal force into the coupling working chamber through the discharge openings arranged along a large diameter. Thus, during the starting period the `working `thereof `in particular, tho arrangement shown in Fg- '1 oomprisos o driving shaft y1 .bovins vanaod .thereto a 4duced in the desired manner.

disc 2 which carries the impeller 3. The turbine wheel 4 is mounted on the driven shaft 5 and is enclosed by the casing' connected to the impeller 3. Sealings or gaskets 7 and 8 seal the couplingtoward the outside and prevent ,the coupling fluid from escaping, The inner diameter D3 ofthe vturbine bladingY is smaller-than the inner diameter D1 of the impeller blading. The radially innermost portion 9 of the turbine wheel chamber directly communicates with a first container 10 also called the accumulator chamber. The container 10 or accumulator chamber is located withinV the innerdiameter D1 of the pump-wheel blading and the walls thereof rotate, and more specifically, inthis instance rotate together with the impeller. In addition to the accumulator chamber 10 there is also provided a second container 11 formed bythe walls 12, 13 and 14 rotating together with the impeller. v The chamber of said second container 11 is located Within the medium diameter of the impeller blading. The said chamber of container 11 communicates with the working chamber of the hydraulic cou- -pling through passages 15 along the greatest diameter.

Theiwall 12 rotating with the impeller is furthermore provided with vents or passages 16 which extend from the entrance edge of the impeller blading up to approxi- .mately the middle of the container 11.

The purpose of these vents consists in allowing an air exchange between the working chamber of the coupling and the 4container 11, and also facilitates the filling and discharging of this container 11. If desired, the vents may consist of separate tubes not shown in the drawing which .pass from the medium range (core chamber) of the irworking chamber-of the coupling into the central portion of the container 11.

- Operation The impeller rotates at high speed and imparts the lknown vortex ring motion upon the coupling fluid, at

which motion the uid within the impeller blading flows outwardly, then impinges upon the turbine blading, and between the latter is deflected inwardly. At low slip 'values, i. e. when impeller and turbine wheel have ap- 'the iow.Y p At low slip, i. e. within the normal working lrange,`the power transmission is effected at low losses.

.At high coupling slip, however, the fluid in the turbine wheel is due to the low secondary speed and therefore blow centrifugal force passed far radially inwardly according to the arrow 18and partly into the accumulator' chamber 10 representing the first rotating container "whereby the vortex flow is greatly braked and additionally the Working chamber of the coupling is at least partly emptied whereby the transmitted torque is re- As soon as the slip again drops to its normal low value, at which the impeller and turbine wheel rotate again at about equal speed, also the vortex flow occurs again in an undisturbed manner in conformity with the arrow 17. The fluid in the accumulator chamber 10 will then be thrown outwardly by centrifugal force into the working chamber which latter is thus filled again to the normal extent. The advantageous effect of the accumulator chamber is particularly clearly shown by the graphs of Fig. 2. The curve 19 of Fig. 2 pertains to a coupling according to the vinvention and illustrates the course of the torque conveyed by the coupling over the slip of the coupling. For purposes of comparison, also the slip-torque curve 20 0f a normal hydraulic coupling with the same outer diameter has been shown. Within the main working range, i. e. Vat'low slippage, the two curves coincide. However, with-increasing slip, vthe curve 20 of' the ordinary hydraulic coupling increases up to a multiple, sometimes ten to twenty-fold, of the normal torque transmitted at a slip of about 3%. In contrast thereto, the curve 19 rather sharply bends and remains at the same level at a slip of 10%' up 'to a slip of 100%. The so-called breakdown torque with the coupling according to the invention is only twice (value 21) the normal torque 22 whereas with an ordinary coupling the breakdown torque 23 is about ten times the normal torque 22. Depending on the dimensions of the inner diameter of the impeller and turbine wheel and the size of the accumulator chamber 10, the characteristics of the hydraulic coupling can be adapted to the respective required conditions. In this way, also other multiples for the breakdown torque can be obtained with regard to the normal coupling torque. Furthermore, by correspondingly selecting the quantity of the coupling fluid, the desired effect can be influenced.

The second rotating container 11 becomes effective during the standstill only of the hydraulic coupling. In this instance the coupling uid collects in the lower portion of the working chamber (blading chamber) and lof the container 11. If then the drive motor is made effective and suddenly rotates the impeller, only a portion of the entire coupling fiuid is available in the working chamberof the coupling for conveying the torque. In other words the fluid in the container 11 is missing in the working chamber of the coupling. Only gradually the Huid in container 11 is rotated by friction with the wall and by means of the centrifugal force gradually being built up is thrown into the Working chamber of the coupling through the connecting passages 15. As a result of thisarrangement, therefore, the torque transmitting capacity is shortly after the motor has been made effective only partially'available and only gradually in'- creases to its maximum value. In this way an overload of the drive during the starting period is avoided which overload may for instance cause current impulses or an undesired voltage drop when the drive is effected with short circuit rotor motors.

By correspondingly dimensioning the connecting passages between the container 11 and the blade chamber of the coupling, the time within which the fluid passes from said container 11v into the annular working cham- -ber may be adjusted at random to adapt the coupling t the respective requirements. t

Fig. 3 shows by means of a graph the infiuence of the second rotating container 11. The motor torque at fully open throttle Mm is plotted over the motor speed nm. The transmittable` hauling torque (torque with turbine wheel braked down) adapted to be transmitted by an ordinary hydraulic coupling, i. e. without rotating container, is represented by the parabola Ms which intersects the motor-torque curve Mm at point A at aspeed nA. This means that with the vehicle at a standstill and at rthe fully open throttle torque, the motor speed is reduced to the speed nA. The lower idling speed of the motor designated -as nLu will when employing a diesel engine be located only slightly below the value nA `so that still a relatively high hauling torque corresponds to the value nLu which torque is characterized by the ordinate ending in the point B. A hydraulic coupling according to the present invention in which temporarily,

`namely within the speed range of from 0 to nA only a motor for instancewith ,short circuit rotor motors about below the pullout torque speed;

The ratio of the inner diameter D1 to the outer diameter D2 of the impeller blading is selected vpreferably greater than 0.4 (see Fig. l). In this instance the design of the impeller blading chamber corresponds to the actual shape of the vortex ring as it is encountered during normal operation, i. e. low slip. The coupling will then particularly meet the requirement of a high degree of transmltting efliciency during normal operation. In this connection it is also advantageous to fill the coupling with a quantity of liquid which corresponds to twice the volume of the impeller blading chamber.

It is furthermore expedient to design the hydraulic coupling as known per se without core guide ring in order during the varying slip conditions to allow the displacement of the vortex llow without any disturbances. Additionally, a very high number of blades may be provided whereby the Wall surface contacted by *the fluid and, therefore, also the ilow resistance at high slip Will be increased. In this way, the effect intended Withtthe coupling according to the invention is further zaided.

The construction of the coupling according tothe in- Avention not only allows a considerable reduction in the filling of the coupling but also` makes it possible that the fluid which heats up `considerably during operation `can expand sufficiently so that only a minor pressure will occur in the coupling which means that the coupling inner chamber can `be sealed in a simple manner.`

i The arrangement of the coupling shown in Fig. 4 corresponds substantially Vto that of Fig. `l with the exception that the Aaccumulator chamber 10 forming the first rotating `container is shielded or screened `with re :gard to `the ,impeller 3 :by a casing or `cup-shaped member 24. In this way, `the fluid in the accumllator chamber will, 4when the `turbine `wheel is at a ,standstill or is rotating slowly, be prevented from being taken along by :the faster running impeller in which instance the fluid `would be thrown back into the working .chamber` by the ,centrifugal force then prevailing.` This arrangement itherefore yields a further reduction in the transmitted `torque and brings about a retardation in the time during which .the `torque `transmitting capacity increases over .the 'arrangement of `a coupling according to Fig. 1. This `effect .can also be obtained or aided by Vindividual blades .25 arranged .in the accumulator chamber and connected 'to the turbine wheel. The. 4accumulator chamber eX- pands in axial direction by about the same amount as `the blading chamber of the impr-:ller` 3. The `air exchange `conduit means `for the chamber `11 `is in this instance formed Iby the `space 26 between the cup-shaped member 24 (which is connected to the turbine wheel and shields `the accumulator 10 with regard to the impeller), and the wall`12 of the impeller.

The drive `of the .impeller 3 is effected by the motor :shaft 1 through the ,intervention of an `elastic Yclutch consisting of a ange 27 and bolts 28 with .rubber sleeving ,29 .which latter is engaged` by sockets 30 provided .in the casing of the impeller. i

`According to the coupling shown inFig. `an annular passage 32 is provided between the wall 31 perpendicu- *lar to the `axis ofthe coupling, and the coupling `shaft 5. The accumulator chamber lliand the container 11 permanently communicate with each other through `said pas- .sage 32. The discharge opening 33 at the largest diameter of the container 11 is `controlled by `a` spring Vrloaded `valve 34 which automatically .opens at a certain impeller speed. The `container 11 thus not only at a standstill of the coupling collects a `portion of the coupling iluidfbut also at high slip a portion of the fluid thrown into `the chamber will pass through passage .32 `intothe container 11. `The fluid accumulated in the `container 11 can, however, dueto the centrifugal force andthe Wall 31 acting likea weir not return into` the working chamber through chambers 10, 9 but can flow `:bac'kfinto -the `working :chamber only after acertain .pri-

mary speed has been exceeded, namely when `the springs 35 allow the valves 34 to open. kIn this way, from the start to a desired speed, a partial emptying of the coupling `working chamber and a `considerable reduction in the ltorque of the coupling is obtained. The Valve `control may, for instance, be adjusted so that the -valve will remain closed from 0 speed up to the lower idling speed of the driving diesel engine but will open as soon as said last mentioned speed has been exceeded.

It is a matter of course that the control of the valves 34 is not limited to the lmanner in which it is effected according to Fig. 5 but may also be effected at random.

Fig. 6 shows an arrangement 1in which also the connecting passages 36 between the accumulator chamber 10 and the second container 11 are controlled by a centrifugally actuated valve 37 in such a `manner that said valves close automatically at a` .certain impeller speed. t

.According to Fig. 7, the valves 37 (and 34 are rigidly interconnected by rod means 38` so` 'that the `valves 37 and 34 will be actuated together. The venting `conduit means for the second rotating container are designated `with the reference numeral 39. s

It is, of course, `understood `that the present invention is, by no means, limited to the particular constructions vshown in the drawings but also comprises any modifications within the scope ,0fY the appended claims.

Whatlclaim is: t s l s 4l. In` combination in `a hydraulic' coupling: a blade equipped impeller confining a `blade chamber, 4shaft means arranged for driving connection with said impeller, Va blade-equipped `turbine wheel confining a blade chamber, the inner diameter ofthe turbine wheel `blading `being less than that of the -impeller blading, said imjpeller together with said turbine wheel conti-ning `the working chamber `of said coupling, `a first `rotatable container located within the inner diameter ;oi:`` said impeller .blading and adapted lto communicate with the radially inner :portion 4of the `blade chamber of said turbine wheel, the axial extension ot `said first rotatable container `being :substantially the same as that of the blade chamber `offsaidl impeller, and a second rotatable container `arranged for `rotation with said `irnpeller `and adapted to .receive a portion of thel `liquid :intended to till said coupling, said second rotatable container `being provided with `passage mea-ns arranged along about `the largest diameter thereof `for effecting communication betweenthe blade lchamber of ,said im.-

peller and the interior of` said second rotatable container thereby: allowing liquidin the workingchamber vof -said coupling during Ythe standstill `of saidfcouplingipahrtly (to Vdischarge intosaid second rotatable container and allowing liquid in said second container during the starting yperiod gradually to return `into said working chamber `through said passage means due to centrifugalforce actingupon the liquid in said second container; t

2. ln combination in a hydraulic coupling: a bladeequipped impeller confining a .bladecharnb'en shaft .means arranged for driving connection with said impeller, a blade-equipped `turbine wheel confining a` blade chamber, the inner diameter of the turbine wheelblading being less than that of the timpeller bieding, said-impeller together with said turbine wheelconiining Vthe working chamber of` said coupling, a `first rotatable `Container located within Vthe innervdiameter of said impeller b1ading and adapted to communicate with thesradiallyv-inner `portion of the blade chamber of said turbine Wheel, ;a

second rotatable container arranged for lrotationvvith said impeller and `adapted to receive :a portionV of the liquid intended to lill said coupling, said `second rotatable container being ,provided with passage means arranged along about the largest diameter thereof for effecting communication between the blade chamber of said impeller a-nd the` interior of said second rotatable `container thereby allowing *liquid in the working chamber of `said coupling during the standstill` of :said coupling 'partly .to discharge into said second `rotatable container and -allowingliquid insaid second container during the starting period gradually to returninto said working chamber through said passage means due to centrifugal force acting upon the liquid in said second container, and air exchange channel means arranged between said working chamber of the coup ling and the second rotatable container.

l 3. A hydraulic coupling according to claim 2, in which said air exchange channel means extend from the fluid entrance edge of said impeller blading to about the central portion of said second rotatable container, said air exchange channel means being formed by wall means connected to said impeller.

4. In combination in a hydraulic coupling: a bladeequipped impeller confining a blade chamber, shaft means arranged for driving connection with said impeller, a 'blade-equipped turbine wheel confining a blade chamber, the inner diameter of the turbine wheel blading being less than that of the impeller blading, said impeller together with said turbine wheel confining the working V'chamber of said coupling, a first rotatable container 1ocated within the inner diameter of said impeller blading and forming one single chamber with the radially inner portion of the blade chamber of said turbine lwheel in such a way that the fiow of the liquid out of the turbine blade chamber which occurs at high slippage is directed into said first rotatable container, said first rotatable container being so dimensioned as to be capable of receiving the total quantity of the liquid which at high slippage is to be removed from the working chamber for the purpose of reducing the transmitted torque, and a second rotatable container arranged for rotation with said impeller and adapted to receive a portion of the liquid intended to fill said coupling, said second rotatable container being provided with passage means having only small ports arranged along about the largest diameter thereof for effecting communication between the blade chamber of said impeller and the interior of said second rotatable container thereby allowing liquid in the working chamber of said coupling during the standstill of said coupling partly to discharge into said second rotatable container and allowing liquid in said second container during the starting period gradually to return into said working chamber through said passage means due to centrifugal force acting upon the liquid in said second container.

5. In combination in a hydraulic coupling: a bladeequipped impeller confining a blade chamber, shaft means arranged for driving connection with said impeller, a blade-equipped turbine wheel confining a blade chamber, the inner diameter of the turbine wheel blading being less thanvthat of the impeller blading, said impeller together with said turbiner wheel confining the working Achamber of said coupling, a first rotatable container located within the inner diameter of said impeller blading and forming one single chamber with the radially inner portion of the blade chamberof said turbine wheel in such a way that the fiow of the liquid out o-f the turbine blade chamber which occurs at high slippage is directed into said first rotatable container, said first rotatable container being so dimensioned as to be capable of receiving the total quantity of the liquid which at high slippage is 'to be removed from the working chamber for the purpose of reducing the transmitted torque, and a second rotatable container arranged for rotation with said impeller, and

working liquid within said coupling, said second con- "tainer being adapted to receive a portion of said liquid andpbeing provided with passage means arranged along about the largest diameter of said second container for effecting communication between the blade chamber of 'said impeller ,and the interior of said second container Vthereby allowing liquid in the working chamber of said coupling during the standstill of said coupling partly to discharge into said second container and allowing liquid in said second container during the starting period gradu -allyto' returninto said working chamber through said passage means due to centrifugal force acting upon the liquid in said second container, Vthe total quantity of liquid in said coupling taking up a volume equaling substanl tially twice the v'olume Yof the blade chamber of said impeller. Y l

6. A hydraulic coupling according to claim 4, in which the ratio between the smallest and the largest diameter of the blading of said impeller is greater than 0.4.

7. A hydraulic coupling according to claim 4, in which the largest diameter of said second rotatable container nearly equals the medium diameter of the impeller blad- 8. A hydraulic coupling according to claim 4, in which the medium diameter of the impeller blading considerably exceeds the largest diameter of said second rotatable container.

9. In 'combination in a hydraulic coupling: a bladeequipped impeller confining a blade chamber, shaft means arranged for driving connection with said impeller, a blade-equipped turbine wheel confining a blade chamber, the inner diameter of the turbine wheel bladingbeing less than that ofthe impeller blading, said impeller together with said turbine wheel confining the working chamber of said coupling, a first rotatable container located within the inner diameter of said impeller blading and forming one single chamber with the radially inner portion of the blade chamber of said turbine wheel in such a way that the flow of the liquid out of the turbine blade chamber which occurs at high slippage is directed into said first rotatable container, said first rotatable container being so dimensioned as to be capable of receiving the total quantity of the liquid which at high slippage is to be removed from the Working chamber for the purpose of reducing the transmitted torque, wall means connected to said turbine wheel and arranged to shield said first rotatable container with regard to said impeller, and a second rotatable container arranged for rotation with said impeller and adapted to receive a portion of the liquid intended to fill said coupling, said second rotatable container being provided with passage means having only small ports arranged along about the largest diameter thereoffor effecting communication between the blade chamber of lsaid impeller and the interior of said second rotatable container thereby allowing liquid in the Working chamber of said coupling during the standstill of said coupling partly to discharge into said second rotatable container and allowing liquid in said second container during the starting period gradually to return into said working chamber through said passage means due to centrifugal force acting upon the liquid in said second container.

l0. In combination in a hydraulic coupling: a bladeequipped impeller confining a blade chamber, shaft means arranged for driving connection with said impeller, a blade-equipped turbine wheel confining a blade chamber, the inner diameter of the turbine wheel blading being less than that of the impeller blading, said impeller together with said turbine wheel confining the Working chamber of said coupling, a first rotatable container located within the inner diameter of said impeller blading and forming one single chamber with the radially inner portion of the blade chamber of said turbine wheel in such a way that the flow of the liquid out of the turbine blade chamber which occurs at high slippage is directed into said first rotatable container, said first rotatable container being so dimensioned as to be capable of receiving the total quantity of the liquid which at high slippage is to be removed from the working chamber for the purpose of vreducing the transmitted torque, auxiliary blade means communication between the blade chamber of said iinpeller and the` interior of said second rotatable container thereby allowing liquid in the working chamber of said coupling during the standstill of said coupling partly Vto discharge into said second rotatable container and allowi ing liquid in said second container during the starting period gradually to return Vinto said working chamber through said passage means due to centrifugal force acting upon the liquid in said second container.

l i 1 1. In combination in a hydraulic coupling: a bladeequipped impeller' confining a blade chamber, shaft means arranged for driving connection with said impeller, `a blade-equipped turbine wheel confining a blade chamber, kthe inner diameter of the turbine `wheel bl'ading being less than that of the impeller blading, saidimpeller together with said turbine wheel confining the working chamber of said coupling, a first 4rotatable container "located within the inner diameter of said yimpeller bladingand forming onesing-le chamber with the radially inner portion of the blade chamber of said turbine wheel in such a way that `the `iiow of the liquid out of the` .turbine blade chamber which 'occurs at high slippage is directed into said `first rotatable container, said iirstrotatable container being so dimensioned as to be capable of receiving the total quantity `of `the liquid which at high slippage is to be removed from the working chamber for the purpose of reducing the transmitted torque, a second rotatable container arranged for rotation with said impeller and adapted to receive a portion of the liquid intended to fill said coupling, said seco-nd rotatable container being provided with passage means having only small ports arranged along about the largest diameter thereof for effecting communication between the blade chamber' of said impeller and the interior of said second rotatable container thereby allowing liquid in the working chamber of said coupling during the standstill of said coupling partly to discharge into said second rotatable container and allowing liquid in said second container during the starting period gradually to return into said working chamber through said passage means due to centrifugal force acting upon the liquid in said second container, and valve means associated With said passage means and arranged for controlling the same.

12. A hydraulic coupling according to claim ll, in which said valve means are arranged for control by centrifugal force.

13. An arrangement according to ciaim 4, which includes: first wall means connected to said turbine wheel and shielding said first rotatable container with regard to said impeller, and second wall means connected to said impeller, said first and second wall means confining air exchange channel means for allowing an exchange of air between the working chamber of said coupling and said second rotatable container.

14. In combination in a hydraulic coupling: a bladeequipped impeller confining a blade chamber, shaft means arranged for driving connection with said impeller, a blade-equipped turbine wheel confining a blade chamber, the inner diameter of the turbine wheel blading being less than that of the impeller blading, said impeller together with said turbine wheel confining the working chamber of said coupling, a first rotatable container 1ocated within the inner diameter of said impeller blading and forming one single chamber with the radially inner portion of the blade chamber of said turbine wheel in such a way that the flow of the liquid out of the turbine blade chamber which occurs at high slippage is directed into said first rotatable container, said first rotatable container being so dimensioned as to be capable of receiving the total quantity of the liquid which at high slippage is to be removed from the working chamber for the purpose of reducing the transmitted torque, a second rotatable container arranged for rotation with said impeller and adapted to receive a portion of the liquid intended to fll said coupling, said second rotatable container being provided with passage means having only small ports arranged along about the largest diameter 4thereof for effecting communication `between the blade chamber of said impeller and the interior of said second rotatable container thereby allowing Vliquid in the working chamber of said coupling during the standstill of said coupling partly to discharge into said second rotatable container and allowing liquid in said second container during the A starting period gradually to return into said working chamber through said passage means due to centrifugal force acting upon the liquid in said second container, and additional passage means directly effecting communication between said `first and said second rotatable containers.

15. A hydraulic coupling according to claim 14, which includes valve means `for controlling said additional passage means. K

1,6. A'hydraulic coupling according to claim 14, which includes tvalve means arranged to be controlled-centrifugally and provided for controlling said additional lpassage means. A i

17. An arrangementaccording to -clalim 4, which includes: additional shaft means rotatably :supporting said impeller, and partition means connected to said impeller and extending -*therefrom in `the direction toward said `additional shaft means `along a `plane substantially per,-

`pendicular vto the `asis of rotation of said impeller, said partition means partitioning said first and second rotatable containers from each other, and the inner edge of said partition means confining with said second shaft means an annular passageway for establishing communication between said first and second rotatable containers.

18. An arrangement according to claim 4, which includes: first valve means arranged for controlling said passage means, additional passage means directly effecting communication between said first and said second rotatable containers, second valve means arranged for controlling said additional passage means, and means operatively interconnecting said first and second valve means.

19. In combination in a hydraulic coupling: a bladeequipped impeller confining a blade chamber, a bladeequipped turbine wheel confining a blade chamber, the inner diameter of the turbine wheel blading being less than that of the impeller blading, said impeller together with said turbine wheel confining the working chamber of said coupling, a first rotatable container located within the inner diameter of said impeller blading and forming one single lchamber with the radially inner portion of the blade chamber of said turbine wheel in such a way that the iiow of the liquid out of the turbine blade chamber which occurs at high slippage is directed into said first rotatable container, said first rotatable Vcontainer being so dimensioned as to be capable of receiving the total quantity of the liquid which at high slippage is to be removed from the working chamber for the purpose of reducing the transmitted torque, a second rotatable container arranged for rotation with said impeller and adapted to receive a portion of the liquid intended to fill said coupling, said second rotatable container being provided with passage means having only small ports arranged along about the largest diameter thereof for effecting communication between the blade chamber of said impeller and the interior of said second rotatable container thereby allowing liquid in the working chamber of said coupling during the standstill of said coupling partly to discharge into said second rotatable container and allowing liquid in said second container during the starting period gradually to return into said working chamber through said passage means due to centrifugal force acting upon the liquid in said second container, first shaft means, second shaft means, one of said shaft means being arranged for driving connection with said impeller and the other of said shaft means rotatably supporting said impeller, and partition means connected to said impeller and extending therefrom in the direction toward one otsajclA shaft meansplong a plane substantially perpendicular tothe-axis of rotation of said impeller, said partition means partitioning said first and second rotatable containers fromeach other, and the inner edge of said partition means confining with one of said shaft means an annular passageway for establishing communication between said first and second rotatable containers.

- v20. In combination in a hydrauliccoupling: a bladeequipped impeller confining an impeller chamber, shaft means arranged for driving connection with said impeller, a blade-equipped turbine wheel confining a turbine chamber, the inner diameter of the turbine wheel chamber being less than that of the impeller chamber, said impeller chamber and said turbine chamber forming the working chamber of said coupling, a first rotatable container located within the inner diameter of said impeller chamber and forming one single chamber with the radially inner portion of said turbine wheel chamber in such a way that the flow of the liquid out of the turbine chamber which occurs at high slippage is directed into said first rotatable container, said first rotatable container being so dimensioned as to be -capable of receiving the total quantity of the liquid which at high slippage is to be removed from said working chamber for the purpose of reducing the'transmitted torque, and a second rotatable container arrangedfor rotation with said impeller and adapted to receive a portion of the liquid intended to ll said coupling, said second rotatable container being pr vided with passage means having only small ports arranged along about the largest diameter thereof for effecting communication between said impeller chamber and the interior lof said second rotatable container thereby allowing liquid in the working chamber of said coupling during the standstill of said coupling partly to discharge into said second rotatable vcontainer and allowing liquid in said second container during the starting period gradually to return to said working chamber through said passage means due to centrifugal force acting upon the liquid in said second container.

References Cited in the le of this patent UNITED STATES PATENTS 2,280,042 Duield Apr. 14, 1942 2,334,282 Peterson et al. Nov. 16, 1943 2,562,657 Blank et al. July 3l, 1951 2,570,768 Clerk Oct. 9, 1951 FOREIGN PATENTS 801,354 Germany Jan. 4, 1951 883,987 Germany July 23, 1953 

